This study will compare two different surgical methods used in total knee replacement with the Unity Total Knee Replacement System. The study will evaluate these two methods based on patients' ability to perform various tasks prior to surgery and at 4 time points during the first 12 months after surgery.
This study will be conducted at a single centre. The study has two treatment groups. One group of 50 knees (approximately 50 subjects) will have a surgical method that uses mechanical alignment (alignment based on how the leg and knee joint move) to determine the proper position of the knee replacement device. The other group of 50 knees (approximately 50 subjects) will have a surgical method that uses anatomical alignment (alignment based on how the anatomy/structure of the leg and knee joint) determine the proper position of the knee replacement device. Subjects will be randomly assigned to one of the two groups. Clinical and functional tests will be conducted pre-operatively and at 6 weeks, 3 months, 6 months and 12 months to determine overall knee function. In addition, a CT scan will be completed pre-operatively and at 6 weeks to assess changes in alignment.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
111
Exeter Knee Reconstruction Unit at the Princess Elizabeth Orthopaedic Centre
Exeter, Devon, United Kingdom
Power of knee extension
Power of knee extension via peak torque of quads measured on a digital myometer.
Time frame: 12 months post-operative
Timed up and go test
The test measures the length of time it takes the subject to rise from a chair, walk 10 feet, turn around, and sit back down in the chair. The subject may rest or use walking aids during the test.
Time frame: 12 months post-operative
Single leg stance (SLS) test
The test measures the length of time the subject can stand on their operative leg.
Time frame: 12 months post-operative
6 minute walk test
The test measures the length of distance a subject can walk in 6 minutes at a pace that does not cause them to become short of breath. Patient may stop and rest if needed, then resume.
Time frame: 12 months post-operative
Timed stairs test
The test measures the length of time it takes a subject to climb up a stair block and down the other side. The subject is asked how difficult the test was on a scale of 0 to 10. The subject can use the rails, if needed.
Time frame: 12 months post-operative
Wii Fit balance test
The subject is asked to stand on a Wii Fit balance board while the "Deep breathing" exercise in the Yoga section is selected. The subject is instructed to follow the instructions on the screen. The subject's score is recorded and the subject is asked how difficult the test was on a scale from 1 to 10.
Time frame: 12 months post-operative
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Ability to kneel
The subject is asked to kneel on a mat on the floor and then rise to a standing position. The subject may use a bench or the floor for balance. After the test, the subject is asked how difficult the test was on a scale of 1 to 10. The subject is allowed to refuse to do the test if he/she feels unable to do so.
Time frame: 12 months post-operative
Sloped treadmill test
The subject is asked to walk on a level treadmill at a comfortable walking speed. The incline of the treadmill is increased until the subject says stop or the limit of the treadmill is reached. The test is repeated with the treadmill in reverse and the subject facing backwards to simulate walking downhill. The subject is asked how difficult the test was on a scale of 1 to 10.
Time frame: 12 months post-operative
Walking on uneven ground
The subject is asked to walk from one end to the other on a specialized track topped with fist-sized pebbles. The subject is allowed to use walking aids. The subject is asked how difficult the test was on a scale of 1 to 10.
Time frame: 12 months post-operative
CT evaluation
CT scan will be done to assess the following anatomical items: * Medial joint line position * Overall limb alignment * Joint obliquity * Rotation
Time frame: 6 weeks post-operative
Power of knee flexion
Power of knee flexion via peak torque of quads measured on a digital myometer.
Time frame: 12 months post-operative
Oxford Knee Score (OKS)
A questionnaire about your ability to perform daily functions.
Time frame: 12 months Post-operative
Knee Injury and Osteoarthritis Score (KOOS)
A questionnaire to assess your ability to perform activities of different difficulty levels.
Time frame: 12 months Post-operative
EuroQoL 5-dimension Health State (EQ-5D)
A questionnaire to assess your health and well-being.
Time frame: 12 months Post-operative
Patient Satisfaction Score
A questionnaire to assess your satisfaction with your knee implant.
Time frame: 12 months Post-operative